BALLSTENT DEVICE AND METHODS OF USE
What is disclosed are medical devices comprising a rounded, thin-walled, expandable metal structure (“ballstent”) and a flexible, elongated delivery device (“delivery catheter”) and systems and methods of use for treating saccular vascular aneurysms with the medical devices. Ballstents comprised of gold, platinum, or silver that can be compressed, positioned in the lumen of an aneurysm, and expanded to conform to the shape of the aneurysm are disclosed. The external surface of ballstents can be configured to promote local thrombosis and to promote the growth of tissue into and around the wall of the ballstent in order to seal the aneurysm and fix the ballstent in place in the aneurysm. The wall of the ballstent can also be configured to release drugs or pharmacologically active molecules, such as those that promote thrombosis, cell proliferation, extracellular matrix deposition, and tissue growth.
This application is a continuation of U.S. patent application Ser. No. 13/980,276 filed on Sep. 27, 2013, which is a U.S. National application for PCT application PCT/US2012/021621, filed on Jan. 17, 2012, which further claims priority to U.S. Provisional Application No. 61/433,305 filed on Jan. 17, 2011, each of which is incorporated by reference in its entirety.
FIELD OF THE PRESENT DISCLOSUREThe present disclosure relates to a medical device comprising a ballstent and a delivery catheter for the treatment of saccular aneurysms of the vascular system. The present disclosure also relates to various forms of ballstents and delivery catheters, and methods of their manufacture. The present disclosure further relates to methods of treating saccular aneurysms using the various medical devices, whereby the ballstent ultimately remains in the saccular aneurysm. Ballstents are rounded, thin-walled expandable metal structures comprised of a single lobe and designed to fill the lumen of a saccular aneurysm. Ballstents are configured for attachment to delivery catheters, compression, advancement through the vascular system, expansion within lumen of saccular aneurysms, and then separation from delivery catheters. Delivery catheters of various sizes, shapes, materials, and configurations can be used to position a compressed ballstent in a saccular aneurysm and expand the ballstent in the aneurysm by the passage of fluids or solids through the delivery catheter and into the central void or space of the ballstent. Further, the invention relates to components for, and methods of, attaching the ballstent to the delivery catheter, as well as components for, and methods of, separating the expanded ballstent from the delivery catheter, such that the ballstent remains in place in an expanded state within the aneurysm sac while the delivery catheter is removed from the body.
BACKGROUND OF THE PRESENT DISCLOSUREAn aneurysm is an abnormal outward bulging of a blood vessel that can occur anywhere in the body. This bulge weakens the blood vessel wall, making it susceptible to rupture, which results in bleeding or hemorrhage. Aneurysms are common in the arterial circulation of the brain, where they are known as cerebral aneurysms. When cerebral aneurysms rupture, this often leads to a hemorrhagic stroke, and sometimes brain damage and death. Cerebral aneurysms are a common condition, affecting an estimated 2% of the adult population. Approximately 90% of cerebral aneurysms are saccular with a rounded, pouch-like shape. Invasive surgery remains a mainstay in their treatment, with the surgery involving opening the skull and sealing the aneurysms by placing a small surgical clip on the outside of the neck, thereby limiting blood flow into the aneurysm sac.
Alternatively, minimally invasive, catheter-based, endovascular treatments have been developed wherein a series of small metal coils are used to fill the aneurysm sac, effectively stabilizing it. In order to treat a blood vessel or aneurysm with coils, a physician inserts a catheter into a lumen of the vascular system and maneuvers the catheter tip into the aneurysm sac. With the catheter tip in position, the physician passes small coils through the catheter into the lumen of the vessel or the cavity of the aneurysm. Although effective, coiling of saccular cerebral aneurysms has drawbacks. First, coil placement is difficult to control, often resulting in coil protrusion into the parent vessel or coil migration to non-target locations. Second, coils only partially fill the aneurysm sac. The accumulation of thrombus and scar tissue is required to seal the aneurysm, a process that takes weeks to occur and is sometimes incomplete, often resulting in aneurysm recanalization and rupture. Incomplete filling of saccular aneurysms with coils is especially common in the neck region of saccular aneurysms, where coil density can be low and blood flow rates high. Third, numerous coils are usually required to fill the aneurysm, resulting in high costs and long treatment times.
More recently, traditional tubular stents have been adapted for the treatment of cerebral aneurysms. These stents are placed on delivery devices and positioned in the parent vessel adjacent to the aneurysm. These stents are then expanded in the parent vessel with the delivery device, followed by removal of the delivery device. The expanded metal stent acts to seal the neck of the aneurysm and keep blood flow out of the aneurysm sac in order to promote aneurysm thrombosis. Although effective, the use of these “flow diverting” stents has drawbacks. First, the stents may cover and divert blood flow away from important arterial branches adjacent to the aneurysm, sometimes resulting in ischemia and stroke. Second, the stents are a source of thrombus and intimal hyperplasia formation in the parent vessel, which can result in narrowing in the parent vessel lumen, ischemia, and stroke.
Therefore, there remains a need for medical devices, systems, and methods for treating saccular aneurysms, including cerebral aneurysms, which result in a more effective and complete sealing of saccular aneurysms that is more durable and permanent. It is further desired to have medical devices, systems, and methods that seal aneurysm sacs more quickly. Finally, it is desired to have medical devices, systems, and methods that can be performed more easily and in less time, with a lower risk of complications, and at a lower cost, when compared with existing treatments.
SUMMARY OF THE PRESENT DISCLOSUREThe present invention relates to medical devices for the treatment of saccular aneurysms of the vascular system. The medical devices comprise a ballstent, a delivery catheter for delivering and expanding the ballstent, and a component for separating the expanded ballstent and the delivery catheter. The ballstent is a stent-like device with a ball shape. The invention further relates to an expanded ballstent left in the lumen of a saccular aneurysm. Additionally, the invention includes various forms of ballstents, delivery catheters, and components for separation. Further, the invention includes systems and methods relating to the use of the medical devices, as well as kits comprising medical devices and instructions for use. The invention also includes methods of manufacturing ballstents, delivery catheters, and components for separation.
The walls of ballstents can be formed from a variety of expandable, rigid materials, preferably metals. The metal used to make the wall of a ballstent can be selected from the group consisting of gold, platinum, silver, titanium, vanadium, aluminum, nickel, tantalum, zirconium, chromium, magnesium, niobium, scandium, cobalt, palladium, manganese, molybdenum, alloys thereof, and combinations thereof. Other metals can be used so long as they are safe to use as an implanted medical device, can be formed into thin walls, and can be expanded from a compressed state and remain expanded in the body, holding their shape under typical conditions. Preferably, the ballstent is made of a ductile metal such as gold, platinum, silver, alloys thereof, and combinations thereof. In a fully expanded form, the ballstent can be configured in a variety of sizes and shapes, depending on the size and shape of the aneurysm to be treated. With a generally rounded form to the metal ballstent, the medical device can be used to treat focal, eccentric, rounded aneurysmal dilations of blood vessels, a condition also known as saccular aneurysms. Available shapes include, but are not limited to, round, oblong, and irregular. Preferably, the round ballstent can have an expanded diameter ranging from about 2 mm to about 20 mm. The oblong ballstent can have an expanded length of between about 2 mm to about 30 mm. The ballstent wall has a width, or thickness ranging from about 3 μm to about 60 μm. Such width allows for compression into a small volume and facilitates passage through blood vessels and catheters. For example, ballstents can be folded and compressed to a diameter small enough to pass through 3 Fr, 4 Fr, and 5 Fr guide catheters or maneuvered through cerebral arteries.
The expanded shape of the ballstent is designed to completely fill the lumen of a saccular aneurysm. As such, the preferred shape is round, or generally rounded. Also, the expanded ballstent comprises a single lobe to maximize the wall contact between the expanded ballstent and the luminal surface of the aneurysm sac so as to reduce the risk of ballstent migration and reduce the amount of blood that flows between the exterior surface of the ballstent and the inner lining of the saccular aneurysm. For this reason, forms with multiple attached, not proximal, lobes are not preferred. Also for this reason, collapse of an expanded ballstent resulting in decreased wall contact with the inner lining of the aneurysm or decreased filling of the lumen of the aneurysm sac is not preferred.
The wall of the ballstent can be uniform or variable, with the thickness changing at different locations on the ballstent. In some ballstent embodiments, the wall of the region near the attachment to the delivery catheter is thicker than the main body of the ballstent, while in other embodiments this region is thinner.
In other embodiments, the wall of the ballstent is porous. This porosity can be uniformly distributed or can be applied only in certain regions, or in a pattern on the surface. In certain embodiments, a ballstent can have a plurality of pores extending through the entire wall.
In other embodiments, the external surface of the wall of the ballstent contains projections, which in certain instances act to reduce ballstent migration after expansion. These projections may be macroscopic, such as with the hooks or barbs seen on other implanted cardiovascular medical devices such as caval filters. For example, a plurality of projections, such as barbs and hooks, can be located on the exterior layer to anchor the ballstent to the surrounding tissue. In a further embodiment, these projections comprise an expansile metal, such as nitinol. For some embodiments, these projections are microscopic, ranging in length from 0.01 μm to about 57 μm. In other embodiments, these projections are branching and can be made of nitinol or fibers.
The surface of the ballstent wall can be configured to increase local thrombus formation and tissue growth into the ballstent wall in order to secure the ballstent in place and reduce the risk of ballstent migration. The wall of the ballstent can further be configured to release solutions that can include drugs, pharmacologically active molecules, or pharmacologic compositions, such as those that would increase the formation of local thrombus, stimulate cell proliferation or the production of extracellular matrix, or increase the rate or extent of tissue growth, such as tissue growth into pores, or around projections, of the wall of the ballstent.
In one embodiment, the ballstent has an exterior layer located on the exterior surface of the wall. The exterior layer may be made from the same materials as the central layer or wall, or can be made of different materials. The exterior layer may be comprised gold, platinum, silver, alloys thereof, or combinations thereof. The exterior layer may also be comprised of polymer, plastic, latex, rubber, an elastomer, fiber material, and combinations thereof. The exterior layer can have a thickness ranging between about 1 μm to about 59 μm.
In one embodiment, the exterior layer has a porous construction. For embodiments with a porous exterior layer, the exterior layer of the ballstent wall can have a plurality of pores ranging in diameter from about 0.01 μm to about 100 μm. The pores allow tissue to grow into the wall of the ballstent. The pores can be uniformly distributed, or can be applied only in certain regions, or in a pattern on the surface. In another embodiment the exterior layer comprises a plurality of projections. These projections can range in length from about 0.01 μm to about 57 μm. In other embodiments, these projections are branching. The projections allow tissue to grow around portions of the wall of the ballstent. The projections can be uniformly distributed, or can be applied only in certain regions, or in a pattern on the surface.
In one embodiment, the porous exterior layer can be configured to release solutions such as drugs, pharmacologically active molecules, pharmacologic compositions, or other compositions that increase the local formation of thrombus, stimulate cell proliferation or extracellular matrix formation, or tissue growth into pores, or around projections, of the ballstent wall. Examples of such substances include thrombin, platelet-derived growth factor, Ethiodol®, Sotradecol®, and combinations thereof, and can include both solutions and suspensions. The porous exterior layer can be comprised of any other porous material, including metal, that can hold fluid or solid material, including drugs, pharmacologically active molecules, or pharmacologic compositions, or any material that promotes thrombosis, cell proliferation, extracellular matrix productions or tissue growth.
Alternatively, the exterior layer can be more smooth, with limited porosity or projections, such as with a polished metal surface. In one embodiment, portions of the exterior layer can be smooth, while other portions can be porous or contain projections. In one embodiment, this surface variation can have a pattern.
In one embodiment, the ballstent has an interior layer located on the interior surface of the central layer or wall. The interior layer may be made from the same materials as the central layer, or can be made of different materials. The interior layer may be comprised gold, platinum, silver, alloys thereof, or combinations thereof. The interior layer may also be comprised of polymer, plastic, latex, rubber, an elastomer, fiber material, and combinations thereof. The interior layer can have a thickness ranging between about 0.1 μm to about 59 μm. Preferably, the interior layer may be an elastomeric coating that strengthens the wall, reduces the leaking of fluid from the ballstent during expansion, or facilitates folding, compression, or expansion of the ballstent.
In another embodiment, the ballstent wall may include two or more metal regions joined by a flexible polymer and/or elastomer joint. The joint allows for better maneuverability and increased trackability as the ballstent is advanced to the desired location. In other embodiments, the ballstent may include three or more metallic regions that are joined through two or more flexible joints
The ballstent wall defines an opening that allows for the passage of fluid. An attachment between the ballstent and delivery device is formed whereby the void of the ballstent defined by the inner surface of the wall can be joined in fluid communication with the lumen of a hollow cylindrical member of the delivery device which is configured to allow for the proximal end of the lumen to accept a fluid source and for fluid to pass from the fluid source, through the lumen of the hollow cylindrical member of the delivery device, and into the void of the compressed ballstent, resulting in expansion of the ballstent.
In one embodiment, the fluid used to expand the ballstent is water or a saline solution. In another embodiment, the fluid is a solutions of radiopaque contrast material. In another embodiment, solids can be used to expand the ballstent, including solids used in combination with fluids. In one embodiment, the solids used to expand the ballstent, or to reduce subsequent compression of the expanded ballstent, are selected from the group of metallic or polymeric coils or wires, metallic or polymeric expansile structures, beads, balls, microspheres, radially expansive materials, support structures, or combinations thereof. In another embodiment, the fluid that is used to expand the ballstent can contain drugs or pharmacologically active molecules, such as those that catalyze the formation of thrombus, including thrombin. Fluid, as defined, can be a gas, liquid, or combination thereof.
The opening defined by the wall of the ballstent can have a diameter ranging between about 0.25 mm and about 5 mm. Optionally, the ballstent has a neck integral with the wall, whereby the neck defines an opening that can extend away from the main body of the ballstent, such as with an external neck, or may extend into the void of the ballstent, such as with an internal neck. The neck of the ballstent may be configured to remain open at the end of the procedure, or may be configured to be sealed prior to the end of the procedure.
The present invention also includes a delivery device for positioning and expanding the ballstent. Various configurations of delivery device can be used to advance the ballstent to the desired location and expand the ballstent. Preferably, the delivery device is a delivery catheter. The delivery catheter includes one or more hollow cylindrical members that define one or more lumens. The delivery catheter can be constructed as a single-lumen catheter, wherein the single hollow cylindrical member is dimensioned to deliver the ballstent to a desired location and deliver fluid from a fluid source at the proximal end into the void of the ballstent at the distal end. When a single hollow cylindrical member with a single lumen is used, generally the medical device is advanced into position through the lumen of a separate guide catheter, which acts to guide the ballstent portion of the medical device to the desired location in the lumen of the aneurysm. Once at the desired location, the ballstent can be expanded and separated from the delivery catheter so that it can remain in the aneurysm sac while the catheter is removed. For this single lumen embodiment, the catheter does not include a hollow cylindrical member that defines a lumen that is dimensioned to allow for the passage of a guidance member, or guide wire. The wall of the delivery catheter can be comprised of standard catheter materials including a plastic or polymer material such as polyurethane. Further, the wall of the delivery catheter can be additionally comprised of metal reinforcement, such as metal reinforcement that is wound in a coil or braid, or some combination of these materials, as described.
In one embodiment, the delivery device comprises a single lumen delivery catheter wherein the distal end of the delivery catheter is configured to enable a fluid connection between a lumen of the delivery catheter and the void of the ballstent. When the ballstent is compressed, this delivery catheter can advance the compressed ballstent through a guide catheter and into the lumen of the aneurysm sac. The delivery catheter also optionally comprises a wire or obturator of a size that fills at least a portion of the lumen of the catheter. The wire or obturator can further comprise a handle to assist removal of the wire or obturator and enable the passage of fluid through the delivery catheter and into the void of the ballstent to expand the ballstent.
The delivery catheter can also be constructed as a double-lumen catheter, wherein the first hollow cylindrical member is dimensioned to deliver fluid from the fluid source into the void of the ballstent and a second hollow cylindrical member is dimensioned to pass over the guidance member, which acts to guide the medical device to the desired location in the lumen of the aneurysm. The guidance member is typically a flexible guide wire that may have a soft, flexible tip in a straight, angled, or j-shaped tip configuration.
Various methods can be used to compress the ballstent and enable it to travel through the lumen of a separate guide catheter, or through small diameter blood vessels. In one embodiment, the ballstent is folded to form one or more pleats prior to or after attaching the ballstent to the delivery catheter, and the pleats are rolled and compressed, similar to the folding of a non-compliant angioplasty balloon. In another embodiment, the ballstent is flattened into a planar shape, and rolled into a cylindrical shape. In another embodiment, the ballstent is compressed into a compact spherical shape. In another embodiment, the ballstent is folded and compressed into a manner similar to origami. In certain embodiments, the ballstent may be folded and wrapped around the shaft of the delivery catheter.
The ballstent may be attached to the delivery catheter using a variety of materials, components, systems, and methods. The ballstent can be attached to the delivery catheter in a manner wherein the size and shape of the distal end of the delivery catheter and the size and shape of the opening in the ballstent wall are matched so that a friction fit is formed between ballstent and the delivery catheter. In an embodiment of a friction fit, an elastic sleeve or wrap can be placed around the neck of the ballstent and used to further hold the ballstent and the delivery catheter together. In another embodiment of a friction fit, a vacuum can be formed in the catheter to further hold the ballstent and the delivery catheter together. The ballstent can be attached to the delivery catheter using an adhesive, or glue. The ballstent can be attached to the delivery catheter using a weld, or solder. The ballstent can be attached to the delivery catheter by a fitting of mechanical parts on the ballstent and the delivery catheter, such as with a clamp that can be released or with a wire, polymer strand, filament, thread, or string that can be loosened or removed.
After expansion of the ballstent in the lumen of a saccular aneurysm, the ballstent may be separated from the delivery catheter using a variety of materials, components, devices, systems, and methods. For example, the expanded ballstent may be separated from the delivery catheter using components of the medical device, using a separate and distinct medical device, or combinations thereof. The ballstent may be separated from the delivery catheter using a variety of methods including physical methods, mechanical methods, electrical methods, thermal methods, chemical methods, hydraulic methods, sonic methods, and combinations thereof.
By way of example and not limitation, for electrical methods, the medical device can be configured such that electrolysis can be used to dissolve a metal weld or solder between the ballstent and the delivery catheter, or used to dissolve a portion of the metal ballstent itself. In certain embodiments, an elongated, insulated electrolysis wire or insulated conductive wire can carry an electrical current from the proximal end of the delivery catheter to the distal end of the delivery catheter where it may be electrically coupled to the weld or solder, or to the ballstent itself. A portion of the weld or solder, or a portion of the ballstent itself, may lack insulation such that the electrical current traveling through the insulated electrolysis wire will dissolve the portion of the weld, solder, or the portion of the ballstent that lacks insulation, resulting in separation of the ballstent from the delivery catheter. The ballstent can have a neck for example, that can be coated with insulation on the inner wall, outer wall, or both, wherein a strip of conductive material is left exposed, uncoated, or uninsulated and whereby the wire is in electrical contact with the ballstent. During the electrolysis process a portion of the weld material or a portion of the wall of the ballstent may be separated into oppositely charged ions. By way of example and not limitation, for mechanical methods, the medical device can be configured such that the delivery catheter is physically separated from the ballstent by cutting or tearing a portion of the ballstent using a flexible loop of wire, polymer strand, filament, string, thread, or snare, or by using one or more blades. A mechanical separation may also occur where the delivery catheter is physically separated from the ballstent by a disengagement of mechanically mated parts, such as a clamp, or by removing a wire, polymer strand, filament, string, or thread that holds the ballstent and the delivery catheter together. By way of example and not limitation, for thermal methods, the medical device can be configured such that an adhesive bond is warmed, causing the adhesive to melt and allowing for separation of the expanded ballstent and the delivery catheter by subsequently pulling them apart. Separation of an expanded ballstent and a delivery catheter may also occur by applying a hydraulic force, by dissolving a bonding medium with a salt, an acid or base, or a chemical, or by applying sound waves such as focused or pulsed ultrasound waves. Another method, involves perforating the neck prior to usage, so that after expansion, the ballstent can be separated from the delivery catheter by pulling them apart at the line of perforation.
By way of example and not limitation, for attachment by friction bonding, the expanded ballstent and the delivery catheter can simply be pulled apart. By way of example and not limitation, for attachment by an adhesive or glue, the ballstent may be separated from the delivery catheter by mechanical mechanism such as by cutting or tearing a portion of the ballstent or the distal portion of the delivery catheter, by electrolysis of a weld, solder, or a portion of the ballstent, or by warming the adhesive bond, causing it to flow. By way of example and not limitation, for attachment by a weld or solder, the ballstent may be separated from the delivery catheter by electrolysis of a weld, solder, or a portion of the ballstent, or by a mechanical mechanism such as by cutting or tearing a portion of the ballstent or the distal portion of the delivery catheter.
In a particular embodiment, the delivery catheter includes a hollow cylindrical member that defines a lumen. The hollow cylindrical member has a proximal end that is attached or can be attached to a fluid source. The hollow cylindrical member comprises polyurethane, with a reinforcement of metal in the form of a coil or braid, and a wall thickness between about 0.05 mm and 0.25 mm. The defined lumen has a diameter between about 0.4 mm and 1.0 mm. A wire comprised of nitinol with a diameter between about 0.3 mm and 0.95 mm is placed in the lumen. A ballstent with a wall comprising gold, with a wall thickness of 15 μm and an expanded diameter of 6 mm, is attached to the distal end of the delivery catheter by friction in a manner that allows for the formation of a fluid connection between the lumen of the hollow cylindrical member and the void of the ballstent. The ballstent is folded and compressed into a cylindrical shape at the tip of the delivery catheter.
The shape and size of the ballstent may be modified after expansion. For example, prior to separation from the delivery catheter, withdrawing fluid from the void of the ballstent can reduce the size of the ballstent. Also prior to separation, a force can be applied to the ballstent through the delivery catheter by advancing the delivery catheter forward or pulling the delivery catheter back, thus modifying the shape of the ballstent. After separation, an external force can be applied to the ballstent by inflating the balloon portion of a balloon catheter adjacent to the ballstent to modify the shape of the ballstent or push a portion of the ballstent toward the aneurysm. In certain embodiments, this can reduce the amount of ballstent that protrudes from the aneurysm sac into the lumen of the adjacent parent, or native, vessel. Also, the opening of the expanded ballstent can be sealed through a variety of methods, or left open.
The present invention also relates to methods of treating saccular aneurysms, with a medical device comprising a ballstent and a delivery catheter. The method includes the steps of positioning the compressed ballstent in the lumen of an aneurysm sac using a delivery catheter, expanding the ballstent by passing fluid through the delivery catheter into the void of the ballstent, separating the delivery catheter from the expanded ballstent, and removing the delivery catheter while leaving the ballstent in an expanded state within the aneurysm sac.
One method for placement of an expanded ballstent within a saccular aneurysm includes the steps of accessing the vasculature with a needle, inserting a guide wire through the needle, removing the needle, and optionally, inserting a vascular sheath into the blood vessel. The method also includes the steps of advancing a guide catheter over a guide wire until the tip of the guide catheter is within or near the lumen of the aneurysm sac. The method also includes passing the medical device comprising a compressed ballstent and the delivery catheter through the guide catheter and positioning it in the lumen of the aneurysm sac. For this method, the delivery catheter portion of the medical device preferably comprises a hollow cylindrical member with a single lumen configured to allow fluid to pass from the proximal end of the delivery catheter to the distal end of the delivery catheter and into the void of the ballstent, and not configured for a guidance member or guide wire. After the compressed ballstent is in position, the ballstent is expanded by passing fluid through the delivery catheter into the void of the ballstent until the ballstent fills at least a portion of the aneurysm sac. The delivery catheter is separated from the expanded ballstent and removed, while the ballstent remains in place in an expanded state. The guide catheter and sheath are also removed. Resultantly, the ballstent is expanded so that at least 50% to 90% and up to 100% of the aneurysm sac is filled by the expanded ballstent, or alternatively that at least 50% to 90% and up to 100% of the luminal surface of the aneurysm sac is in contact with the expanded ballstent. The instructions may further include the steps of shaping and/or sealing the expanded ballstent. The exterior surface of the ballstent optionally comprises pores or projections. The pores may have a diameter ranging in diameter from about 0.01 μm to about 100 μm. The projections may have a length that ranges between about 0.01 μm to about 57 μm.
Another method for placement of an expanded ballstent within a saccular aneurysm includes the steps of accessing the vasculature with a needle, inserting a guide wire through the needle, removing the needle, and optionally, inserting a vascular sheath into the blood vessel. The method also includes the steps of advancing a diagnostic catheter over a guide wire until the tip of the guide wire is within or near the lumen of the aneurysm sac and removing the diagnostic catheter. The method further includes passing the medical device comprising a compressed ballstent and a delivery catheter over the guide wire, and positioning the compressed ballstent in the lumen of the aneurysm sac. For this method, the delivery catheter portion of the medical device preferably comprises at least two hollow cylindrical members with each associated with a separate lumen, with one lumen configured to allow fluid to pass from the proximal end of the delivery catheter to the distal end of the delivery catheter and into the void of the ballstent, and another lumen configured for a guidance member or guide wire. After the compressed ballstent is in position, the ballstent is expanded by passing fluid through one of the hollow cylindrical members of the delivery catheter into the ballstent until the ballstent is expanded to fill at least a portion of the aneurysm sac. Then the delivery catheter is separated from the expanded ballstent and removed, while the ballstent remains in place in an expanded state. Then the guide wire and sheath are also removed. Resultantly, the ballstent is expanded so that at least 50% to 90% and up to 100% of the aneurysm sac is filled by the expanded ballstent, or alternatively that at least 50% to 90% and up to 100% of the luminal surface of the aneurysm sac is in contact with the expanded ballstent. The instructions may further include the steps of shaping and/or sealing the expanded ballstent. The exterior surface of the ballstent optionally comprises pores or projections. The pores may have a diameter ranging in diameter from about 0.01 μm to about 100 μm. The projections may have a length that ranges between about 0.01 μm to about 57 μm.
The invention includes a kit with a medical device comprising a ballstent and a delivery catheter, and instructions on use. The medical device optionally further comprises components for separation of the expanded ballstent and the delivery catheter. In one embodiment, the instructions include the steps of placing a guide catheter near or within the lumen of the aneurysm sac, passing the medical device through the guide catheter, and positioning the compressed ballstent in the lumen of the aneurysm sac. After the compressed ballstent is in position, the instructions further include the steps of expanding the ballstent until it fills at least a portion of the aneurysm sac, followed by separating the expanded ballstent from the delivery catheter, and removing the delivery catheter, while the ballstent remains in the aneurysm sac in an expanded state. The instructions may further include the steps of shaping and/or sealing the expanded ballstent. In another embodiment, the instructions include the steps of placing a guide wire near or within the lumen of the aneurysm sac, passing the medical device over the guide wire, positioning the compressed ballstent in the lumen of the aneurysm sac, and removing the guide wire. After the compressed ballstent is in position, the instructions further include the steps of expanding the ballstent until it fills the aneurysm sac, followed by separating the ballstent from the delivery catheter, and removing the delivery catheter, while the ballstent remains in the aneurysm sac in an expanded state. The instructions may further include the steps of shaping and/or sealing the ballstent.
In other embodiments, the invention includes a method of manufacturing the ballstent. The method may include forming the wall of the ballstent through electroforming or electroplating on a cylindrical mandrel, a tapered mandrel, or a mold. The method may further include forming exterior or interior layers through electroforming, electroplating, sputtering, vapor deposition, or combinations thereof. The method for forming the external layer may further include methods to form pores or projections. The method further includes the steps of contacting the ballstent with a solution or suspension of a pharmaceutical, drug, or pharmacologically active molecules such that pharmaceutical, drug, or pharmacologically active molecules remain with the ballstent during placement of the ballstent in an aneurysm, thereby delivering the pharmaceutical, drug, or pharmacologically active molecules to a saccular aneurysm. With this method, after positioning the expanded ballstent in the lumen of the aneurysm sac and leaving it in place, at least some of the molecules leave the ballstent and diffuse into the surrounding cells, tissues spaces, or fluids.
As such, a medical device comprising a ballstent and a delivery catheter is provided that can be used to treat a saccular aneurysm of a blood vessel.
The present invention relates to a medical device comprising an expandable metal structure known as a “ballstent” and a delivery catheter. The ballstent is a thin-walled stent-like device that can be expanded into a semi-rigid form that can remain in the body for an extended period. Specifically, the ballstent is configured for use in filling and sealing saccular aneurysms of blood vessels, especially saccular cerebral aneurysms. The delivery catheter is configured to deliver the ballstent to an aneurysm and to provide a pathway, through the lumen of a hollow cylindrical member or lumen, for fluid to move into the void of the ballstent, in order to expand it and fill at least a portion of the lumen of the aneurysm sac.
A round embodiment of the ballstent 100 is shown in
An embodiment of the medical device 500 is shown in
As shown in
Another round embodiment of the ballstent 100 is shown in
Another embodiment of the medical device 500 is shown in
As shown in
The medical device 500 can be used as part of various systems, methods, and medical kits. These systems, methods, and medical kits can be used to treat saccular arterial aneurysms, such as a saccular cerebral aneurysm. Alternatively, these systems, methods and medical kits can be used to treat a variety of medical conditions. In one embodiment, the systems, methods, and medical kits can be used to occlude biological conduits in patients in need thereof, the biological conduits including arteries, veins, vascular structures, ducts, airways, bile ducts, pancreatic ducts, enterocutaneous fistulas, ureters, fallopian tubes, and urethras, among others. The medical kit includes the medical device and instructions for use. The medical kit may also contain additional components for carrying out a variety of treatments using the medical device 500.
A typical method for using the medical device 500 to treat a saccular aneurysm includes accessing the vascular system of a human with a needle, passing a guidance member, or guide wire, 302 into the vessel, optionally placing a vascular sheath, advancing the medical device comprising a compressed ballstent 100 and a delivery catheter 300 or 400 and advancing it until the compressed ballstent is located in the lumen 701 of an aneurysm sac 700. Then the ballstent 100 is expanded by passing a fluid, liquid, gas, or solid material, or combinations thereof, through the delivery catheter and into the central void or space 108 of the ballstent. The delivery catheter and the expanded ballstent are then separated and the delivery catheter is removed from the body, while the expanded ballstent remains in place within the lumen 701 of the aneurysm sac 700. The position of the ballstent 100 during and after the procedure may be monitored by any suitable methods, including fluoroscopy, computed tomography, MRI and ultrasound, including intravascular ultrasound.
The BallstentThe ballstent 100 may be composed of a single continuous layer or wall 122, as shown in
Alternatively, the ballstent 100 may have an additional coating or layer 104 on the exterior surface 124 of the central layer 122, as shown in
The porous or spongy nature of the exterior layer 104 can contain (or be configured to contain) solutions that include drugs, pharmacologically active molecules, or pharmaceutical compositions within the pores 200. As such, solutions such as drugs, pharmacologically active molecules, or pharmaceutical compositions can be delivered to the treatment site. Drugs, pharmacologically active molecules, or pharmaceutical compositions that promote thrombosis, stimulate cell proliferation or extracellular matrix production, or tissue growth are examples that can be placed in the pores 200 of the exterior layer 104. The drugs, pharmacologically active molecules, or pharmaceutical compositions are incorporated into the pores 200 of the wall or the exterior layer 104 prior to positioning the ballstent 100 at the desired location. The drug compositions may be delivered into the pores 200 via capillary or wicking action. The pores 200 range from about 0.01 μm to about 100 μm in diameter. Pore diameters for each ballstent may vary according to the specific drugs, pharmacologically active molecules, or pharmaceutical compositions to be incorporated and the desired rate of release from the ballstent in vivo. By way of example and not limitation, the ballstent 100 may have a porous exterior layer 104 where the pore diameter averages from about 0.01 μm to about 0.05 μm, about 0.05 μm to about 0.5 μm, 0.5 μm to about 5 μm, about 5 μm to about 25 μm, about 25 μm to about 100 μm, about 0.05 μm to about 100 μm, or about 0.01 μm to about 100 μm.
The drugs, pharmacologically active molecules, or pharmaceutical compositions may include thrombin, platelet-derived growth factor, Ethiodol®, Sotradecol®, or combinations thereof. Other pharmaceutical compounds and compositions that promote thrombosis, stimulate cell proliferation, stimulate the synthesis of extracellular matrix, or the growth of tissue into the porous external wall of the ballstent 100 may also be used. Such drugs or pharmaceutical compositions may include molecules to promote cell proliferation, extracellular matrix production, or tissue growth, such that the expanded ballstent 100 will become more firmly attached to the tissue at the treatment location. The dosages and manner in which the drugs, pharmacologically active molecules, or pharmaceutical compositions are incorporated into the ballstent wall or exterior layer 104 are a matter of choice depending on the treatment performed. Other compounds may be used to promote blood clotting or thrombosis around the ballstent. For embodiments of the ballstent 100 with a porous layer 104, over time, the ballstent 100 remains expanded with the ballstent eventually becoming affixed to the surrounding tissue. The exterior surface of the ballstent may also comprise one or more projections, as described, that can increase the strength of the attachment of the expanded ballstent to the adjacent tissue, and thereby reduce the risk of ballstent movement or migration. The projections may have a length that ranges between about 0.01 μm to about 67 μm, and can have a branched construction. In some embodiments, the projections are rigid, or semi-rigid. In other embodiments, the projections are flexible and hair-like, and may further comprise globular ends, similar to the projections on the surface of the footpad of the gecko.
Alternatively, the ballstent 100 may comprise an additional layer or liner 1400 on the interior surface 106 of the central layer 122, as shown in
Advantageously, the ballstent 100 can be delivered into the lumen 701 of a saccular aneurysm 700, expanded, and then separated from the delivery catheter 300, such that the delivery catheter can be removed while the ballstent remains in place filling a portion, substantially all, or all of the lumen of the aneurysm in an expanded state. The expanded ballstent 100 will typically conform to the shape of the saccular aneurysm cavity in which it is placed. The expanded ballstent 100 can also be shaped with external force, such as a physical force applied by the inflated balloon portion 1102 of an adjacent balloon catheter 1100, as shown in
As illustrated in
Various expanded ballstent shapes are acceptable, as required to treat saccular aneurysm of various shapes, including circular, oblong, and irregular, so long as the shape is generally rounded and the expanded ballstent comprises a single lobe. Regardless of the formed shape, when a ballstent is expanded in the lumen or cavity 701 of an aneurysm sac 700, the ballstent is designed to conform, at least partially, to the shape of the cavity.
In various embodiments, the dimensions of the ballstents 100 are selected based upon the size and shape of the saccular aneurysm being treated. Preferred shapes of the ballstent 100 include round, oblong, and irregular. The diameter of the round expanded ballstent 100 ranges from about 2 mm to about 30 mm, and preferably has an expanded diameter ranging from about 2 mm to about 20 mm. The expanded length of oblong ballstents preferably ranges between about 2 mm to about 30 mm. The ballstent 100 may have an expanded volume that ranges between about 0.001 cc to about 63 cc. In preferred embodiments, the expanded diameter of the round ballstent 100 ranges from about 2 mm to about 10 mm, while the preferred expanded volume ranges from about 0.004 cc to about 40 cc. In preferred embodiments, the expanded length of the oblong ballstent 100 ranges between about 2 mm to about 30 mm.
In other embodiments, one or more portions of the ballstent wall 102 may be thicker than the remaining portions of the wall. By way of example and not limitation, the wall in the middle of the body of the ballstent may be thicker or thinner than the wall in the proximal and distal portions of the ballstent, or the wall of a neck may be thicker or thinner than the main body of the ballstent. Optionally, the entire ballstent wall can be porous, as shown in
The ballstent comprises a central wall or layer 122, optionally with an exterior wall or layer 104, and also optionally with an interior wall or layer 1400, as shown in
In one construction, the central layer or wall 122 of the ballstent 100 is continuous and comprised of gold. To this preferred construction, an exterior layer 104 comprised of porous gold can be added. Additionally, an interior layer 1400 comprised of Parylene™ may be present. In certain embodiments wherein electrolysis is used to separate the expanded ballstent 100 from the delivery catheter, certain portions of the ballstent (such as the neck or body) are coated with an insulator or polymer, such as Parylene™ (including the external surface, the internal surface, or both the internal and external surfaces) while a portion of the neck or body remains uncoated or uninsulated. In this instance, the uncoated or uninsulated portion is solubilized by the passage of an electrical current into the uncoated or uninsulated during electrolysis. In certain embodiments, the uncoated or uninsulated portions are created by masking during the coating process. In other embodiments, the coating or insulation is removed from the uncoated or uninsulated portions, as through etching or ablation, such as with laser etching or laser ablation.
The central void or space 108 of the ballstent 100 can be filled with fluids, solids, or combinations thereof. A fluid is a substance having particles that easily move and change their relative position without a separation of the mass. Fluids that can be used to expand the ballstent 100 include liquids, gases, and combinations thereof. By way of example and not limitation, the fluid may be water, a saline solution, a radiographic contrast solution, or a mixture thereof. In one embodiment, the fluid may further include a solution or suspension of a drug, pharmacologically active molecules, or a pharmaceutical preparation. By way of example and not limitation, the drug, pharmacologically active molecules, or a pharmaceutical preparation may increase local thrombosis, cell proliferation, extracellular matrix production, or tissue growth into or around the wall 102 of the expanded ballstent 100 when it is positioned in the lumen of a saccular aneurysm.
In one embodiment, the shape of an expanded ballstent is maintained by placing solid material or support structures into the central void or space 108 of the expanded ballstent 100. Examples of this solid material include metal or polymeric coils or wires, metal or polymeric solid support structures, radially expansile materials, beads, particles, spheres, or microspheres. In certain embodiments, these solid materials can also be used to help expand the ballstent. In other embodiments, these solid materials are added after the ballstent expansion. In one embodiment, as shown in
Embodiments of the ballstent can include features designed to secure the ballstent in place once it has been expanded in the lumen of an aneurysm sac. These features can be biological or physical, or a combination thereof. In one embodiment, the exterior surface 110 of the ballstent 100 may be coated with molecules that can bind to adjacent thrombus or tissue. These molecules can be affixed to the ballstent through a variety of methods, including chemical bonds such as with hydrogen bonding or covalent bonding. Alternatively, these molecules can be affixed to the ballstent through encapsulation of a porous layer or encapsulation of projections. Representative molecules that can be affixed to the wall of ballstents include fibrin, and molecules that can link to fibrin through covalent and non-covalent bonding. With such a coating, the ballstent can be anchored to the fibrin-rich clot that forms between the aneurysm and the ballstent. In another embodiment, the ballstent 100 may comprise a porous external layer or wall 104 or a wall with external projections to promote thrombus formation on the external surface 110 or in the pores 200 of the ballstent and promote cell proliferation, extracellular matrix production, or tissue growth into or around the wall 102 of the ballstent 100 such that the ballstent 100 will, over time, become more strongly attached to the tissue in the adjacent aneurysm wall. As shown in another embodiment, the exterior surface 124 or 110 of the ballstent 100 further comprises one or more projections therefrom, which can be used to anchor the ballstent 100 to the surrounding tissue, specifically the wall a saccular aneurysm, and hold the ballstent in the desired location. In a macroscopic form, the projections may be composed of nitinol or any other suitable biocompatible material. The projections may be straight, curved, hook-shaped, or configured as pigtail hooks 1800 as shown in
In order to facilitate advancement of the ballstent through the vascular system, some embodiments of the ballstent 100 comprise two or more metallic portions 1900A-B that are joined by a flexible joint 1902, as shown in
In order to facilitate advancement of the ballstent through the vascular system, the ballstent 100 can be compressed into various shapes and dimensions. Optionally, this compression can include various forms and patterns of folding or pleating. For example, one or more pleats can be made in the ballstent 100 and then the pleats can be wrapped into a cylindrical shape. Alternatively, the ballstent 100 may be flattened into a planar shape and then rolled into a cylindrical shape. Alternatively, the ballstent 100 may be compressed into a compact spherical shape. Additionally, the portions of the ballstent 100 may be twisted or braided during compression. In certain instances, the ballstent may be compressed around the delivery catheter 300, as in
In
In various embodiments, the ballstent 100 is attached to the delivery catheter 300, 400, then the pleats are formed, and then the pleated folds are wrapped and compressed onto the delivery catheter 300, or the obturator 404. In another embodiment, the ballstent 100 is first folded to form pleats, then attached to the delivery catheter 300, 400, and then the pleated folds are wrapped and compressed onto the outer surface of the delivery catheter 300, or obturator 404. In another embodiment, the ballstent 100 may be folded and compressed into a variety of shapes in a manner similar to Japanese origami, as shown in
In certain embodiments, the ballstent 100 is fully expanded to treat a saccular aneurysm. In other embodiments, the ballstent 100 need not be fully expanded to treat a saccular aneurysm, but may successfully seal the aneurysm while partially expanded. In all embodiments, the ballstent remains in an expanded state (partially or completely) after detachment from the delivery catheter. An expanded state refers to the at least partial distention of the ballstent 100, such as at least 20%, 50%, 75%, or 90% and up to 100% of the maximum ballstent volume.
By way of example and not limitation,
The central layer 122 of the wall of the ballstent 102, the interior layer 1400, and the exterior layer 104, may be formed by any suitable method. For example, in a preferred embodiment, the central layer 122 of the wall 102 is formed by electroforming or electroplating. A conductive mandrel is placed in a solution of metal ions, which coat the mandrel to form a layer of the ballstent 100. The shape of the ballstent 100 can be modified by modifying the shape of the mandrel. The thickness of the central layer 122 of the wall 102 can be modified by varying the process time. Regions of different wall thicknesses and the pattern of thickness differences may be produced by masking. In other exemplary methods of forming the ballstent 100, the central layer 122 of the wall 102 of the ballstent 100 may be formed by vapor deposition, wherein vapors from one or more polymers, pure metals, or metal alloys are condensed upon a substrate or mold (not shown). The mold may be removed to provide a hollow shell composed of the pure metal or metal alloy.
An exterior layer 104 may be formed on the outside of the central layer 122 of the ballstent 100 by additional electroplating or electroforming, by vapor deposition, or by sputter deposition, wherein material is eroded from a target (e.g., a metal or metal alloy) and is then deposited onto a substrate (e.g., a mandrel or mold) forming a thin layer on the substrate.
An interior layer 1400 may be formed on the inside of the central layer 122 of the ballstent 100 by additional electroplating or electroforming, or by vapor deposition, or by sputter deposition.
An exterior layer 104 may be formed on the outside of the central layer 122 of the ballstent 100 by additional vapor deposition. In some instances, the central layer 122 may be formed by electroforming or electroplating and the interior or exterior layers are formed by vapor deposition.
In some instances, it may be desirable to incorporate an elastomer layer into the ballstent 100, either as an interior or an exterior layer. In these instances, the elastomer can be added by incorporating a pre-formed material into the desired orientation, or by vapor deposition, or other methods.
The wall 102 of the main body of the ballstent 100 may be formed by different methods than the neck 116. The central layer 122 of the ballstent 100 may be formed by different methods than the exterior layer or coating 104 or the interior layer or coating 1400.
Two-dimensional sheets of metal may be manipulated and secured in the desired configuration to form the wall 102 and/or the exterior layer 104. These two dimensional sheets may further comprise rubber, plastic, polymer, woven or knitted fiber materials, or other materials, or combinations thereof. By way of example and not limitation, one or more two-dimensional sheets of a metal may be folded into a ballstent shape and welded, soldered, glued, or bonded together. Similarly, two-dimensional sheets of material may be manipulated and secured to form the exterior layer 104 or the interior layer 1400.
In various embodiments wherein the wall 102 of the ballstent 100 comprises metal, an annealing process is used to improve ductility and facilitate folding, compressing, and/or expanding the ballstent 100. By way of example and not limitation, a typical annealing process includes heating the ballstent 100 at approximately 300° C. for a period of about one hour, followed by an immediate quench in distilled water at room temperature.
The Delivery CatheterThe ballstent 100 is advanced and positioned within human body by an elongated portion of the medical device known as the “delivery device”. A delivery device is an elongated surgical instrument that defines at least one lumen, or potential lumen, having a proximal and a distal end that is dimensioned to deliver fluid from a fluid source at the proximal end into the central void or space 108 of the ballstent 100, which is attached to the distal end. Further, any medical device or component of a medical device that can position the ballstent 100 at a desired location in the vascular system, such as the lumen of a saccular aneurysm, facilitate the expansion of the ballstent, and then facilitate the separation of the ballstent from the delivery device is generally acceptable as a delivery device. Typically, the delivery device is a catheter (a “delivery catheter”). Preferably, the delivery catheter may be any flexible catheter, hollow wire, removable core wire, or combinations thereof, suitable for accessing locations with the vascular system, including the delivery catheters 300 and 400. The delivery catheter may also be any other type of catheter, hollow wire, or removable core wire, or alternatively a needle or trochar, or combinations thereof, suitable for accessing locations with the vascular system.
A catheter is a flexible, tubular, elongate medical device configured for insertion into bodily compartments, including blood vessels, to permit the injection or the withdrawal of fluids, amongst other functions. Catheters are often comprised of polymers or plastics and optionally further comprise metal, such as in a coil or braid configuration. Catheters can be configured to enable attachment to ballstents, facilitate the delivery of compressed ballstents to the lumen of an aneurysm sac, facilitate the expansion of compressed ballstents, and separate from expanded ballstents. The delivery catheter 300 or 400 can be configured to pass through the vascular system with the attached ballstent 100 in a compressed form, as shown in
Preferably, the delivery device is a catheter 300 and 400, as shown in
As shown in
For some embodiments, the medical device is advanced in the body over a guidance member 302, as shown in
As shown in
As shown in
The dimensions of the delivery catheter 300 or 400 are a matter of design choice depending upon the size of aneurysm to be treated and the location of the aneurysm in the vascular system. The distance between the aneurysm to be treated and the site of insertion of the delivery medical device into the vascular system, will determine, in part, the length of the delivery catheter 300 or 400. Delivery catheter lengths range between 5 cm and 300 cm, with preferable ranges between 75 cm and 225 cm. The smallest diameter blood vessel segment in the path between the site of insertion of the medical device into the vascular system and the aneurysm to be treated, will determine, in part, the diameter of the delivery catheter. Delivery catheter diameters range between 2 Fr and 7 Fr, with preferable ranges between 3 Fr and 5 Fr.
In some embodiments, the proximal end of the delivery catheter 400 is configured with a Luer hub or taper 406 or 308 that may facilitate a Luer-Lok™ or Luer-Slip™ type connection for connecting a fluid source, such as a syringe 314, to the lumen 312 of a hollow cylindrical member configured to transmit fluid from the proximal end of the delivery catheter to the central void or space of the ballstent 100. As shown, in
Attaching the Ballstent to the Delivery Catheter and Separating the Expanded Ballstent from the Delivery Catheter
The ballstent 100 may be attached to, or engaged with, the delivery catheter in a variety of ways. For example, the ballstent 100 may be affixed to the delivery catheter by a friction fit, using an adhesive or glue, by a weld or solder, by a junction or uniting of components, or by the application of a compressive force from a clamp, ring, elastomer sleeve or wrap, or compressive balloon. Various methods and devices may be used to separate the expanded ballstent from the delivery catheter. By way of example and not limitation, these methods and devices may be broadly categorized as physical or mechanical, electrical, thermal, chemical, hydraulic, and sonic.
In one embodiment, a physical or mechanical attachment is made between a ballstent and a delivery catheter, wherein the coupled parts are configured to fit tightly together and remain together by friction. After expansion of the ballstent, the physician slips the distal end of delivery catheter out of the neck of the ballstent to effect separation, a process that may be facilitated by moving a guide catheter 800 forward to abut the expanded ballstent 100 prior to withdrawing the delivery catheter, as shown in
In another embodiment, as shown in
In another embodiment, the ballstent 100 is attached to the distal end of the hollow cylindrical member 306 of the delivery catheter 400 with an adhesive, glue, weld, or solder. In this embodiment, the expanded ballstent 100 is separated from delivery catheter 400 by mechanical methods. The expanded ballstent 100 may be separated from the delivery device by a number of mechanical methods that cut, tear, or otherwise physically degrade a portion of the ballstent to separate the remainder of ballstent from the delivery catheter 400.
As shown in
In another embodiment shown in
In another embodiment shown in
In another embodiment, shown in
In another embodiment, a ring structure is fixed to the distal end of the delivery catheter, while a second ring structure is fixed to the proximal end of the ballstent, with a mating of the two rings attaching the ballstent to the delivery catheter. After expansion of the ballstent, the rings can be disengaged, resulting in separation of the expanded ballstent 100 and the delivery catheter. The unlocking of the rings could be accomplished by actuating a spring-loaded clamp or other similar methods in order to release the ballstent.
In other embodiments, hydraulic methods may be used to separate the expanded ballstent 100 from the delivery catheter device. In one embodiment, the expanded ballstent 100 separates from the delivery catheter after fluid is injected through a lumen to actuate a mechanical joint between the ballstent 100 and the delivery catheter, resulting in separation of the expanded ballstent 100 and the delivery catheter.
In one embodiment, a mechanical attachment is made between a ballstent and a delivery catheter wherein a portion of the ballstent is attached to the distal portion of the delivery catheter using one or more welds or solder 316 that are not insulated, and sensitive to electrolysis. For this embodiment, an electrolysis wire 320 or an insulated conductor wire extends along the length of the delivery catheter from the proximal end of the delivery catheter 300 or 400. The electrolysis wire 320 or an insulated conductor wire can electrically couple a source of electrical current outside the patient's body to the weld or solder that attaches the ballstent to the delivery catheter. In this way, the electrolysis wire 320 or the insulated conductor wire is in electrical communication with the weld or solder that attaches the ballstent to the delivery catheter. In various embodiments, the insulated conductor wire or the electrolysis wire 320 can lie within the wall of the delivery catheter 300 or 400, along the exterior surface of the delivery catheter, or within a lumen of the delivery catheter. The electrolysis wire 320 or insulated conductor wire is in electrical communication with the weld or solder between the ballstent and the delivery catheter. In some embodiments, the electrolysis wire 320 is insulated, wherein the weld or solder is not insulated. In some embodiments, the electrolysis wire 320 and the ballstent 100 are insulated, while the weld or solder 316 is not insulated. In other embodiments, the electrolysis wire 320 and the weld or solder 316 is insulated, but a portion of the ballstent 100 is not insulated. An electrical current is applied to the electrolysis wire 320 or the insulated conductor wire after the ballstent 100 is expanded. The current is applied in an amount and for a time sufficient to dissolve at least a portion of the weld or solder and separate the delivery catheter from the ballstent 100, leaving the ballstent expanded at the desired position while the delivery catheter is removed. In another embodiment, the current is applied in an amount and for a time sufficient to dissolve at least a portion of the ballstent and separate the delivery catheter from the ballstent 100, leaving the ballstent expanded at the desired position while the delivery catheter is removed. In one embodiment the current is a direct current (DC) while in another embodiment, the current is an alternating current (AC). The electrolysis wire 320 or the insulated conductor wire is in electrical communication with the weld or solder 316. In this embodiment, a DC current is applied to the insulated conductor wire or the electrolysis wire 320 after the ballstent 100 is expanded. The DC current dissolves at least a portion of the weld or solder 316, resulting in separation of the ballstent 100 and the delivery catheter, and leaving the ballstent 100 expanded at the desired position while the delivery catheter is removed.
In another embodiment, as shown in
In another embodiment, a mechanical attachment is made between a ballstent and a delivery catheter wherein a portion of the ballstent is attached to the distal portion of the delivery catheter using one or more bonds that are sensitive to chemical dissolution. The bonding medium may be composed such that the bonding medium dissolves when contacted by a solution with a high salt concentration, an acid, a base, or a specific chemical. By way of example and not limitation, a cover or other shielding device may be removed from the region where the ballstent 100 is joined to the delivery catheter to expose the bonding medium. Also by way of example and not limitation, injection or infusion of a solution with a high salt concentration, an acid, a base, or a specific chemical to the region of the bonding, after expansion of the ballstent at the desire location can result in dissolution of the bonding medium and separation of the expanded ballstent and the delivery catheter.
In another embodiment, a mechanical attachment is made between a ballstent and a delivery catheter wherein a portion of the ballstent is attached to the distal portion of the delivery catheter using one or more bonds that are sensitive to chemical dissolution. The bonding medium may be composed such that the bonding medium dissolves when contacted by a solution with a high salt concentration, an acid, a base, or a specific chemical. By way of example and not limitation, a cover or other shielding device may be removed from the region where the ballstent 100 is joined to the delivery catheter to expose the bonding medium. Also by way of example and not limitation, injection or infusion of a solution with a high salt concentration, an acid, a base, or a specific chemical to the region of the bonding, after expansion of the ballstent at the desire location can result in dissolution of the bonding medium and separation of the expanded ballstent and the delivery catheter.
In another embodiment, a mechanical attachment is made between a ballstent and a delivery catheter wherein a portion of the ballstent is attached to the distal portion of the delivery catheter using one or more adhesives, glues, bonds, welds, or solder that are sensitive to sonic waves. In this embodiment, the bond between the ballstent 100 and the delivery catheter is broken using sound waves, such as focusing pulsed ultrasound waves, resulting in separation of the delivery catheter and the expanded ballstent.
In one embodiment, the wall opening of the expanded ballstent 100 is left open at the end of the procedure. In other embodiments, the wall opening of the expanded ballstent 100 is closed prior to the end of the procedure. By way of example and not limitation, an opening may be sealed by applying an external force, such as with the inflation of the balloon portion of a balloon catheter adjacent to the expanded ballstent. Alternatively, an opening may be sealed by snugging a loop of flexible material around the external surface of the neck of the ballstent 100 prior to separation of the expanded ballstent and the delivery catheter. In this method, the loop of material may comprise a wire, polymer strand, filament, string, thread, or snare.
According to any of the methods where the ballstent 100 is separated from delivery catheter, one or more radiopaque markers may be incorporated into the appropriate portions of the ballstent or delivery catheter to assist in the positioning of the ballstent, expansion of the ballstent, separation of the expanded ballstent from the delivery catheter, and removal of the delivery catheter after separation. For example, a radiopaque marker band or spot may be incorporated into the medical device to identify the location where separation is intended to occur. In addition, radiopaque material may be incorporated into the ballstent. Also, a radiopaque spot or marker band or spot may be incorporated into distal end of the delivery catheter so that the tip of the delivery catheter can be seen under fluoroscopy while pulling the delivery catheter away from the expanded ballstent. A radiopaque spot or marker band may also be placed onto the detachment components, as need be. The radiopaque marker may be comprised of various radiodense materials, including but not limited to a metal band, a metal spot or line, or a line of barium.
According to any of the methods where the ballstent 100 is separated from delivery catheter, one or more radiopaque markers may be incorporated into the appropriate portions of the ballstent or delivery catheter to assist in position of the ballstent, expansion, separation of the expanded ballstent from the delivery catheter, and removal of the delivery catheter after separation. For example, a radiopaque marker band or spot may be incorporated into the medical device to identify the location where separation is designed to occur. In addition, radiopaque material may be incorporated into the ballstent. Also, a radiopaque marker band or spot may be incorporated into distal end of the delivery catheter so that the tip of the delivery catheter can be seen under fluoroscopy while pulling the delivery catheter away from the expanded ballstent. A radiopaque marker may also be placed onto the detachment components, as need be. The radiopaque marker may be comprised of various radiodense materials, including but not limited to a metal band, a metal spot or line, or a line of barium.
METHODS OF USEThe shape of a ballstent 100 that has been expanded in the lumen of a saccular aneurysm is determined, in part, by the formed shape of the ballstent. For example, in some embodiments, the ballstent 100 is manufactured into a round, oblong, irregular, or non-spherical orientation to match the contours of the cavity for a particular saccular aneurysm 700. The expanded shape is also determined by the size and shape of the lumen of the saccular aneurysm. The expanded shape can also be determined by the application of an external force, such by inflating the balloon portion of a balloon catheter adjacent to the expanded ballstent. In certain embodiments of the methods, the balloon portion 1102 of a balloon catheter 1100 is inflated in the lumen of the parent blood vessel 1202 adjacent to the expanded ballstent 100 in the lumen of the aneurysm sac, thereby pushing the wall 1104 of the ballstent 100 toward the aneurysm. In other embodiments, the ballstent 100 is manufactured into a non-spherical orientation to match the contours of the cavity for a particular saccular aneurysm 700.
In all embodiments, the expanded shape of the ballstent 100 is determined by the following factors: 1) the manufactured shape of the ballstent 100; 2) the degree of ballstent expansion; 3) the size and shape of the aneurysm 700; and 4) the effect of any applied external force on the ballstent after expansion. By way of example and not limitation, the manufactured size and shape of the ballstent 100 may be determined by making measurements of the aneurysm 700. The measurements can be made by using medical images, including two dimensional and three dimensional reconstructions, and standard distance reference markers. Other methods of measuring the aneurysm may also be used.
In another embodiment, the position, size, and shape of the expanded ballstent can be manipulated while positioned within the aneurysm 700. In this embodiment, it is not necessary to determine the precise contours of the aneurysm 700 prior to inserting the ballstent 100. The ballstent 100 is shaped by the degree of expansion of the ballstent and the application of external forces. For example, an external force may be applied by inflating the balloon portion of a balloon catheter adjacent to the expanded ballstent, or by tools inserted through or around the delivery catheter 400 or guide catheter 800. In other embodiments, the ballstent 100 may be shaped in a step prior to or after the step of separating the expanded ballstent from the delivery catheter 400.
In embodiments, the ballstent is designed so that the exterior surface 110 or 124 of the expanded ballstent 100 makes contact with a substantial portion of the inner surface 704 of the aneurysm 700. In some embodiment, the exterior surface 110 or 124 of the ballstent 100 makes contact with at least 50%, 75%, 90% or more of the inner surface 704 of the aneurysm 700, including up to 100%. In embodiments, the expanded ballstent is designed to fill the lumen of the aneurysm sac 701. In one embodiment, the expanded ballstent 110 fills at least 50%, 75%, 90% or more of the volume of the lumen 701 of the aneurysm 700, including up to 100%.
In all embodiments, the ballstents are configured to maintain their expanded shapes and expanded ballstents are not designed for, or intended to be, compressed or flattened into disc-like structures before or after separation from the delivery catheter.
By way of example and not limitation, a method of using the device 500 to treat a patient may include the steps of examining a patient and collecting diagnostic medical images to identify a saccular aneurysm. The vascular system may be accessed using any suitable method including accessing an artery using the Seldinger technique. A guide wire 302 is then inserted into the vascular system. Then a guide catheter 800 is inserted into the vascular system and advanced into or near the lumen of the saccular aneurysm. The position and luminal dimensions of the saccular aneurysm are then visualized by an intra-arterial injection of radiographic contrast solution under fluoroscopy. The guide wire 302 is removed and the medical device 500 is then inserted through the guide catheter 800 until the compressed ballstent is advanced into the lumen 701 of the aneurysm 700. The ballstent 100 is then expanded in the lumen 701 of the aneurysm 700. A radiographic contrast solution may be injected into the parent vessel 1202 of the aneurysm 700 to confirm that the size of the expanded ballstent 100 is appropriate and that it is properly positioned in aneurysm. Once proper placement and sizing of the expanded ballstent 100 has been confirmed, the expanded ballstent is separated from the delivery catheter 300 or 400 by any of the methods disclosed herein, and the delivery catheter is removed. The expanded ballstent 100 is left in the patient, where subsequent examination may be conducted to determine if additional treatment is necessary. The expanded ballstent 100 left in the patient functions to prevent bleeding or expansion of the aneurysm, and as such it alleviates future medical problems the patient might experience had the aneurysm 700 not been treated.
By way of example and not limitation, a method of using the device 500 to treat a patient may include the steps of examining a patient and collecting diagnostic medical images to identify a saccular aneurysm. The vascular system may be accessed using any suitable method including accessing an artery using the Seldinger technique. A guide wire 302 is then inserted into the vascular system. Then a guide catheter 800 is inserted into the vascular system and advanced with the guide wire 302 until the guide wire 302 is positioned in or near the lumen of the saccular aneurysm. The position and luminal dimensions of the saccular aneurysm are then visualized by an intra-arterial injection of radiographic contrast solution under fluoroscopy. The guide catheter 800 is removed and the medical device 500 is then inserted over the guide wire until the compressed ballstent 100 is advanced into the lumen 701 of the aneurysm 700. The guide wire 302 is removed. The ballstent is expanded 100 in the lumen 701 of the aneurysm 700. A radiographic contrast solution may be injected into the parent vessel 1202 of the aneurysm 700 to confirm that the size of the ballstent 100 is appropriate and that it is properly positioned in aneurysm. Once proper placement and sizing of the expanded ballstent 100 has been confirmed, the expanded ballstent is separated from the delivery catheter 300 or 400 by any of the methods disclosed herein and the delivery catheter is removed. The expanded ballstent 100 is left in the patient, where subsequent examination may be conducted to determine if additional treatment is necessary. The expanded ballstent 100 left in the patient functions to prevent bleeding or expansion of the aneurysm, and as such it alleviates future medical problems the patient might experience had the aneurysm 700 not been treated.
In various embodiments, a medical kit may be provided for treating a patient with the medical device. The medical kit may include the medical device 500, a guide wire 302, one or more guide catheters 800, one or more ballstent support structures, and methods for separating the expanded ballstent 100 from the delivery catheter 300 or 400 including separate medical devices for separation, components of the medical device 500 for separation, and methods of use. The medical kit may further include instructions for use.
Two or more ballstents 100A-B may be used in combination to fill the lumen or void 701 of the aneurysm sac 700, as illustrated in
A hypothetical method for using the medical device 500 to treat a patient having a saccular cerebral aneurysm may begin with one or more pre-surgical consultations, where a number of tests may be performed. The tests may include blood tests, urine tests, an electrocardiogram, and imaging tests including a head CT, a head MRI, and a cerebral angiogram, among others. From the diagnostic imaging tests, images and measurements of the aneurysm may be obtained demonstrating the position, size, and shape of the aneurysm. The consultations may occur several days before, or on the same day, that the procedure is performed.
On the day of the procedure, the patient is prepared for the procedure and typically given local anesthesia. The patient's groin is then prepped and draped in an aseptic manner. Then a physician accesses a femoral artery in the patient with a micropuncture set. A 0.035″ soft tip guide wire 302 is inserted in a retrograde fashion into the femoral artery. A 6 Fr vascular sheath is placed. A 5 Fr diagnostic catheter is advanced over the guide wire until the tip of the 5 Fr diagnostic catheter is in the lumen of the saccular cerebral aneurysm, where it can act as a guide catheter 800. While the physician is positioning the guide catheter 800, a surgical assistant prepares the ballstent portion 100 of the medical device by wetting the porous exterior layer 104 of the ballstent with a solution containing thrombin. The medical device 500 is advanced through the guide catheter 800 and positioned in the lumen 701 of the aneurysm sac 700. The tip of the guide catheter 800 is pulled back, exposing the compressed ballstent 100. After the compressed ballstent 100 is in the desired position, the compressed ballstent is expanded by injecting a saline solution through the lumen 312 of the delivery catheter 300 or 400 and into the central void 108 of the ballstent until the ballstent expands to fill at least a portion of the aneurysm. The physician obtains an angiogram of the aneurysm 700 and the parent artery 1202 by injection of radiographic contrast material in order to confirm that the expanded ballstent 100 is positioned properly within the lumen 701 of the saccular aneurysm 700 and fills the aneurysm adequately. The physician then connects the proximal end of the electrolysis wire 320 or the insulated conductor wire to a DC power source and applies a current to the electrolysis wire or insulated conductor wire which is electrically coupled to the neck 116 of the ballstent 100 in an amount, and for a time sufficient, to result in the dissolution of a circumferential strip of the neck of the ballstent that is uncoated and without insulation, resulting in separation of the expanded ballstent and the delivery catheter. The physician obtains another angiogram of the aneurysm 700 and the parent artery 1202 in order to confirm that the expanded, released ballstent 100 is positioned properly within the lumen of the saccular aneurysm and fills the aneurysm adequately. The physician removes the delivery catheter 400, and the guide catheter 800. The physician advances a balloon catheter 1100 over the guide wire 302 until the balloon 1102 is adjacent to the expanded ballstent 100. The balloon portion 1102 of the balloon catheter 1100 is then inflated with a saline solution until it fills the lumen of the parent artery 1202 and flattens and pushes the wall 1104 of the expanded ballstent 100 toward the aneurysm 700. The physician obtains another angiogram of the aneurysm 700 and the parent artery 1202 in order to confirm that the expanded, released ballstent is positioned properly within the lumen of saccular aneurysm, fills the aneurysm adequately, and that the lumen of the parent artery 1202 is free of obstruction. The physician withdraws the balloon catheter 1100, the guide wire 302, and the sheath and achieves hemostasis of the femoral artery puncture with compression. The patient is then transported to a recovery room. During and after recovery, the physician periodically monitors the patient as well as the position of the metal ballstent 100 and the completeness of the sealing of the aneurysm 700.
It will be appreciated that the devices and methods of the present invention are capable of being incorporated in the form of a variety of embodiments, only a few of which have been illustrated and described above. The disclosures herein may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive and the scope of the present invention is, therefore indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Claims
1. A medical device for occluding a saccular aneurysm, the medical device comprising:
- a catheter;
- a compressed, hollow metal structure, wherein the hollow metal structure, when expanded, assumes a generally rounded form, comprises a single lobe having a wall with an interior surface defining a void, and an exterior surface, with an opening in the wall that allows for the passage of fluid from the catheter into the void;
- wherein the catheter is dimensioned to allow for the passage of a guidance member, or guide wire;
- wherein the passage of fluid from the catheter into the void of the compressed hollow metal structure results in expansion of the hollow metal structure; and
- wherein the expanded hollow metal structure has sufficient rigidity to remain in an expanded state when detached from the catheter and implanted in vivo in an unsealed configuration.
2. The medical device of claim 1, wherein the hollow metal structure comprises a polymer layer or coating.
3. The medical device of claim 3, wherein the thickness of the polymer or coating is between 0.1 μm and 59 μm.
4. The medical device of claim 3, wherein the thickness of the metal layer is between 5 μm and 20 μm.
5. The medical device of claim 3, wherein the total thickness of the wall is between 2 μm and 60 μm.
6. The medical device of claim 3, wherein the polymer layer or coating is external to the metal layer.
7. The medical device of claim 3, wherein the polymer layer or coating is internal to the metal layer.
8. The medical device of claim 1, wherein the hollow metal structure has an expanded diameter ranging from 2 mm to 20 mm.
9. The medical device of claim 1, wherein the exterior surface of the hollow metal structure comprises microscopic projections.
10. The medical device of claim 9, wherein the projections range in length from 0.01 μm to 57 μm.
11. The medical device of claim 1, wherein the exterior surface of the hollow metal structure is porous.
12. The medical device of claim 11, wherein the pores have a diameter of 0.01 μm to 0.5 μm.
13. The medical device of claim 1, wherein the hollow metal structure comprises one or both of a proximal neck and a distal neck.
14. The medical device of claim 13, wherein the hollow metal structure comprises both a proximal neck and a distal neck and both the proximal neck and the distal neck of the hollow metal structure project away from the body of the hollow metal structure.
15. The medical device of claim 14, wherein the proximal neck of the hollow metal structure is formed by different methods than the body.
16. The medical device of claim 1, wherein a portion of the wall of the hollow metal structure is formed by electroforming.
17. The medical device of claim 1, wherein the central layer of the hollow metal structure is formed by different methods than an exterior layer or coating, or an interior layer or coating.
18. The medical device of claim 1, wherein the hollow metal structure comprises an outer layer comprising metal and an inner layer comprising a polymer and wherein the metal layer and the polymer layer are bonded together.
19. The medical device of claim 1, wherein the hollow metal structure is annealed.
20. The medical device of claim 1, wherein the diameter of the catheter or catheter assembly and the compressed hollow metal structure prior to expansion is 2-5 Fr.
21. The medical device of claim 1, wherein the wall of the catheter or catheter assembly is reinforced with wound or braided wire.
22. The medical device of claim 21, wherein the wire is comprised of stainless steel or nitinol.
23. The medical device of claim 1, wherein the length of the catheter or catheter assembly is 75-225 cm.
24. The medical device of claim 1, wherein a radiopaque marker band or spot is incorporated into the medical device to identify the location where separation of the hollow metal structure and the catheter or catheter assembly is designed to occur.
25. The medical device of claim 1, wherein a radiopaque marker band or spot is incorporated into the medical device to identify the distal end of the catheter or catheter assembly.
26. The medical device of claim 1, wherein the compressed hollow metal structure can be expanded by injection of a fluid comprising water or saline into the void of the hollow metal structure at a pressure less than 5 atmospheres.
27. The medical device of claim 1, wherein the hollow metal structure is attached to the catheter or catheter assembly by an adhesive, or glue.
28. The medical device of claim 1, wherein an insulated conductor wire for transmitting an electrical current extends from at least a proximal end of the catheter or catheter assembly to at least a distal end of the catheter or catheter assembly along a longitudinal axis of the catheter or catheter assembly and configured in a manner wherein, when the hollow metal structure is in a human patient, the passage of electricity through the conductor wire can dissolve a portion of the proximal neck of the hollow metal structure by a method of electrolysis and allow for separation of the expanded hollow metal structure and the catheter or catheter assembly.
29. The medical device of claim 28, configured such that the conductor wire passes a DC current.
30. The medical device of claim 28, wherein the portion of the proximal neck of the hollow metal structure that is dissolved comprises a strip of exposed conductive material.
31. The medical device of claim 30, wherein the strip of exposed conductive material is produced by etching or ablation.
32. The medical device of claim 31, wherein the etching or ablation is made by a laser.
33. The medical device of claim 1, wherein the expanded hollow metal structure is supported by a rigid or semi rigid material inside the void of the expanded hollow metal structure.
34. The medical device of claim 1, wherein the expanded hollow metal structure is not supported by a rigid or semi rigid material inside the void of the expanded hollow metal structure.
Type: Application
Filed: Feb 20, 2017
Publication Date: Sep 14, 2017
Patent Grant number: 10537451
Inventors: F. Nicholas Franano (Olathe, KS), Katherine J. Stephenson (Los Gatos, CA)
Application Number: 15/437,273
